Energy Boost: 7 – I was looking forward to a rocket fueled energy rush similar to the Stacker 2 – Black Jax shot; after all, caffeine IS the fourth most abundant ingredient in the little 8 oz can (carbonated water, high fructose corn syrup, citric acid, CAFFEINE). However, while there is a noticeable lift in alertness and energy it is not much more than a Red Bull.